Thread safe bean

Question

My business logic bean is being accessed via jsp's
It looks something like this
public class MyBean
private int myInt;
private String MySting;
* Bean sets and gets
public void setMyInt(int i)
myInt = i;
public void setMyString (String s)
myString = s;
public int getMyInt()
return myInt;
public String getMyString()
return myString;
* Public wrapper for private business logic
public void doSomethingWrapper()
myString = doSomething(getMyInt())
* Private business logic
private String doSomething(int i)
// business Logic
return a_string;
Now, I've been told that this is not thread safe and that will not work. My big concern is
with making the Bean properties thread safe, anyone way any suggestions? Thanks in advance.

Answer 1

Based on your requirement, i see a necessicity for session scoping the bean.
And yes in servlet/jsp multiple thread can act on single instance of a bean.
So what you do is add synchronized keyword for the getter and setter method. For example if have modify your example given above, it would look something like this
public class MyBean
private int myInt;
private String MySting;
* Bean sets and gets
public synchronized void setMyInt(int i)
   myInt = i;
public synchronized void setMyString (String s)
   myString = s;
public synchronized int getMyInt()
   return myInt;
public synchronized String getMyString()
   return myString;
* Public wrapper for private business logic
* You dont necessarily have to synchronze this method because
* getMyInt() is anyway synchronized.
public void doSomethingWrapper()
   myString = doSomething(getMyInt())
* Private business logic
* If you dont access any properties(member variables) dont synchronize, if you do then yes
private String doSomething(int i)
   // business Logic
   return a_string;
}By adding synchronized keyword the java virtual machine ensures method level serial execution, so no corruption problem.
But you require more than method level synchronization, then you need some other mechanism like semaphore and just.
In most of the case, former would be just enough but if your case is not so then let me know, I can suggest other mechanism which suit your needs